package com.atguigu.juc;

import java.util.concurrent.CountDownLatch;

/**
 * CountDownLatch：闭锁，在在完成某些运算时，其他所有线程的运算全部完成，当前运算才继续执行
 */
public class TestCountDownLatch {

    public static void main(String[] args) {
        CountDownLatch latch = new CountDownLatch(5);

        LatchDemo latchDemo = new LatchDemo(latch);

        long start = System.currentTimeMillis();

        for (int i = 0; i < 5; i++) {
            new Thread(latchDemo).start();
        }

        try {
            latch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        long end = System.currentTimeMillis();

        System.out.println("耗时：" +  (end - start));


    }

}

class LatchDemo implements Runnable{

    private CountDownLatch latch;

    public LatchDemo(CountDownLatch latch){
        this.latch = latch;
    }

    @Override
    public void run() {

        synchronized (this){
            try{
                for (int i = 0; i < 50000; i++) {
                    if (i % 2 == 0) {
                        System.out.println(i);
                    }
                }
                System.out.println("-----------------");

            }finally {
                latch.countDown();
            }
        }
    }


}
